This project addresses itself to a pressing problem in immunology, i.e., the development of methods of specifically treating diseases in which immune reactants play a pathogenic role. We have recently developed several innunoadsorbents to which immune reactants have been chemically conjugated or physically entrapped. Each of these immunoadsorbents has received extensive in vivo trial in an extracorporeal circulation system in rabbits or dogs. Nylon microcapsules to which DNase has been conjugated have shown a capacity to hydrolyze DNA circulating free or in a DNA: anti-DNA complex. DNA-cellulose agarose immunoadsorbent columns have demonstrated a capacity to specifically reduce DNA antibody levels in actively immunized rabbits. A third immunoadsorbent in which soluble glomerular basement membrane antigen was entrapped in collodion-charcoal, markedly ameliorated passively induced nephrotoxic glomerulonephritis in dogs. Methodology for conjugation of antibodies to a non-toxic cellulose membrane has been developed and proven functional in vivo. In addition, tumor specific antibodies have been isolated and methodology for testing specificity in vitro and in vivo have been developed. The objectives of this study are to apply this newly developed technology to effect the specific removal of actual or potential pathogenic immune reactants from the circulation in experimental and naturally occurring autoimmune and neoplastic diseases in dogs. Careful evaluation of in vitro studies will enable us to select and utilize the appropriate immunoadsorbent(s) to maintain the circulation clear of pathogenic immune substances. Clinical and serologic assessment of this mode of treatment on the total disease process will be carried out to determine the effectiveness of prolonged treatment. If these experimental trials are successful, and toxicity studies prove negative, similar extracorporeal technology may be applicable to the treatment of various autoimmune and neoplastic diseases in humans.